1. A smart shopping system
SmartKart
A smart shopping system
Group G (Group 25)
Victoria Abreu - CS Christina Heagney - CpE
Lucas Ryan - CS Doran Senior - CpE

2. Project Motivation: What is the problem? Why do we care?
Currently, shopping can be a hassle:
Waiting in long checkout lines
Spending time collecting coupons
If on a budget, keeping track of subtotal manually
With all these factors, a simple task like
shopping becomes hectic and wastes
time.
Our SmartKart shopping system is
a solution to this.

3. Project Overview: Our Goal
Motivated by the Amazon Go Supermarket, our project is a portable, lower-cost alternative.
The SmartKart will:
Remove the issue of long lines
Assist users by providing coupons available at the current store
Display the cost of the products in their shopping cart

4. What is a SmartKart?
The SmartKart is a portable system that interfaces with a mobile app to improve the shopping experience:
RFID technology will track items that have been added/removed from the cart
Upon exiting the store, the customer's account will be charged, and an electronic receipt will be generated
GPS will monitor the cart’s current location to help prevent theft
The app will store the current coupons available, account information, and handle payment transactions

5. Project Requirements: General
The overall shopping cart shall be no bigger than 45"H x 25"W x 25"D
The overall system shall weigh no greater than 50 lbs
The overall system shall cost no more than $500 to build
The user shall be able to grasp the functionality of the UI in approximately one minute
The device will allow users to purchase at least 25 items at a time

6. Overall System Design r

7. Hardware

8. RFID System
RFID sensors and tags will keep track of all items a shopper adds/removes from their shopping cart
Each item will have a unique RFID tag
The RFID sensor will be placed on the inside railing of the shopping cart

9. RFID Comparison Device Dimensions Range Frequency Price
RFID Reader ID-3LA
0.7” x 0.8”
Up to 4”
125 kHz
$25.95
PN532 NFC/RFID
2.1" x 4.7"
13.56 MHz
$35.95

10. GPS/Locking System
A GPS/Locking system will be used to help prevent theft of carts
GPS will determine if a shopping cart has traveled outside of the store’s perimeter
If so, the lock will engage, and cart will lose mobility

11. GPS Comparison Device Satellites Update Rate Position Accuracy
Tracking Sensitivity
U-Blox NEO-6M GPS Module
50 channels
5 Hz (max)
N/A
-161 dBm
Adafruit Ultimate GPS Breakout
22 Tracking w/ 66 channels
1-10 Hz 3m
-165 dBm

12. Voltage Regulators (TSR1-24XX Series)
Two DC/DC step-down regulators
12V to 5V
12V to 3.3V
Up to 91% efficiency
Low power dissipation

13. WiFi Module
Once an item is scanned, the WiFi module sends the following via a POST request to an HTTPS server:
Store ID (12 bytes)
Cart ID (12 bytes)
Product ID (7 bytes)

14. WiFi Module Comparison
Device
Connectivity Range
Interface
HTTPS Enabled
Cost
ESP
~1,000 feet
Serial No
$6.99
Adafruit ATWINC1500
~800 feet
Serial, SPI
Yes
$24.95
ESP e
$6.95

15. Power Distribution Power Patrol Sealed Lead Acid Battery Volts 12V
Current
5 Ah
Battery Life
20 hours
Dimensions
3.5 x 2.8 x 4 in

16. Microcontroller Comparison
Device
Operational Voltage
Memory
Speed
I/O Pins
Power Consumption
Price
MSP430G2553
1.8V – 3.6V
16 KB FLASH
0.5 SRAM
16 MHz 24
Active Mode:
230μA w/ 1 MHz
Off Mode: 0.1μA
$9.99
ATmega2560
4.5V – 5.5V
256 KB FLASH
4 KB EEPROM
8 KB SRAM 86
500μA w/ 1 MHz
$45.95
ATmega328P
1.8V – 5.5V
32 KB FLASH
1 KB EEPROM
2 KB SRAM
20 MHz 23
0.2mA w/ 1 MHz
$24.95

18. System Prototype

19. PCB Trace Widths: 36 mil for 2A load current 8 mil for signal traces
Ground plane on top/bottom layers
Connected with vias
Screw terminals for RFID, power, and locks

21. Embedded Software GPS (ATmega328P) GPS is updated every 1 second
Used to detect if cart position is outside of range
If so, locks are enabled
RFID Sensor (ATmega328P)
RFID sensor checks for tags every ½ second
Tag data is sent to server to determine item add/remove
A checksum is done on RFID tag for error detection
Tag data is then sent to WiFi module via serial
WiFi Module
Relay/lock is automatically set to high until a WiFi connection is established
Relay is then set to low/off
Module checks data on serial buffer
Checksum is performed for error detection
Data is then sent over to HTTPs server via POST request

22. Software

23. UI Design
Using Angular
Created a Progressive Web App

24. UI Design
Apple IPhone 6 Emulator
Nokia Lumia Emulator

25. System Architecture MongoDB (Database) Express (Web Server)
Angular (FrontEnd)
Express-jwt (Web Tokens)
Socket.io (Web Sockets)
Stripe (Payment processing)
S3 (File storage)

26. Business Logic
Bind user with selected cart in database and create their virtual shopping cart
Web sockets to update user’s running cart as they add/remove items from their cart
When users are being cashed out, we charge their card on account to the selected store’s bank account via Stripe
Users can view stores’ products and coupons, as well as calculate the cost of their shopping list in real time

27. Database Collection: Products Coupons Store Information Account
Purchases
Storing payment sources (bank account/credit/debit cards) tokens from stripe for PCI compliance
Storing aws s3 url to account receipts to improve lookup time

28. Administrative Content

29. Work Distribution Component Primary Secondary Power Doran Senior
Christina Heagney
GPS
Locking Mechanism
RFID System
PCB
Database
Lucas Ryan
Victoria Abreu
Payment System
Communication
User Interface

30. Budget Total: $390.09 OBJECT QUANTITY EST. COST RFID Scanner 1 $39.95
RFID Tags 50
$19.20
GPS 66 Channel Breakout Board
Arduino Uno 2
$44.00
PCB 5
$120.00
Wifi Module
$4.00
Payment System
$50.00
Shopping Cart
$40.00
BreadBoard (830 pins)
$2.99
Voltage Regulator
$30.00
Total: $390.09

31. Issues Encountered Hardware: Longer range sensor is more expensive
RFID sensor does not have a long enough range
Longer range sensor is more expensive
Software:
Mapping Store coupons to products
Structure data that queries coupon products effectively that can scale well
Solution: keep id of all the coupons and products a store currently accepts/offers and filter through those arrays

32. Questions?

33. Demo (Video): GPS Lat/Lon Range Detection